Two-Phase Query Rewriting Based Approximate XML Query Algorithm
Gao Hongjiang · Dianzi xuebao · 2007
A two-phase query rewriting based approximate XML(extensible markup language) query algorithm is proposed.The algorithm can not only return the exact answers,but also return the sequence of approximated answers with similarity degree.Firstly,through the strategy of scheme rewriting,an original query tree is rewritten into query trees with different XML DTDs(document type definition) so as to solve the problem of semantic loss due to the heterogeneous XML data.Secondly,the transformed query trees derived by the sequences of the basic transformation operations are used to perform exact embeddings into XML data tree,so as to transform the problem of approximate XML query into the problem of exact XML query for transformed query trees.Thirdly,XML data distribution statistics based similarity degree computing model and optimization algorithm for TopK problem are given.Finally,the experiments of intelligent design of automobile shape show our algorithm outperforms the SSO algorithm.